The history and evolution of instrumented spinal fusion in the entire human spine has been reviewed in related pending application Ser. No. 12/471,345, filed on May 22, 2009, application Ser. No. 12/471,340, filed on May 22, 2009, Ser. No. 12/054,335 filed on Mar. 24, 2008, Ser. No. 11/842,855, filed on Aug. 21, 2007, Ser. No. 11/536,815 filed on Sep. 29, 2006, and Ser. No. 11/208,644 filed on Aug. 23, 2005, the contents of which are hereby incorporated by reference in their entirety.
Conventionally, the majority of posterior cervical, and posterior and lateral, thoracic and lumbosacral fusion techniques, as well as anterior and/or lateral thoracic/lumbosacral fusion techniques are typically supplemented with pedicle screw placement.
Complications of pedicle screw placement in the spine include duration of procedure, significant tissue dissection and muscle retraction, misplaced screws with neural and/or vascular injury, excessive blood loss, need for transfusions, prolonged recovery, incomplete return to work, and excessive rigidity leading to adjacent segmental disease requiring further fusions and re-operations.
Recent advances in pedicle screw fixation including minimally invasive, and stereotactic CT image-guided technology, and the development of flexible rods, imperfectly address some but not all of these issues.
Complications of anterior plating/instrumentation in the anterior lumbar spine include potential devastating injury to the major vessels due to chronic vascular erosion of major vessels, or acute vascular injuries due to partial or complete plate and or screw pull-out. Recent advances including diminishing plate width and/or profile, and absorbable plates/screws, imperfectly address some, but not all of these issues.
Furthermore, for re-do surgeries, plate removal can be arduous with potential complications of vascular, and/or neural injury and screw breakage.
Lateral access to the lumbosacral spine can be complicated by damage to the genitofemoral nerve. Sensory and motor evoked potential monitoring during this surgery imperfectly address some but not all of these issues.